Discuss Well last straw on the vibration issue after driveshaft and gears on AllFordMustangs.com, the place for Mustang enthusiasts.

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Well after 1 month, lots of time and money dealing with this vibration issue I GIVE UP. I have had Ford dealership, performance shop, 4 individual guys, driveline shop, tire shop all look at my car. Also called axle-exchange, UPR and Spohn Suspension. Of course my driveline RPM is going to increase from changing 3.15 - 3.73 gears.

- My following modifications are Magnaflow 15589 and 16400 love the sound very quiet at highway speeds but very loud when you stomp on it love the exhaust. Really BIG difference in the flow with the offroad x-pipe very impressed. - C&L intake noticed a pretty big difference when I added this as my first mod.- FRPP 3.73 gears massive difference first gear shifts before you can blink by far the best change.- Bama 91 octane race tune is really good for changing the automatic transmission shift points and overall second best mod completed.- UPR Dual adjustable UCA, Spohn Suspension LCA & Panhard bar with polyurethane and del-sphere pivot joint. The LCA are loud but that is typical for this type of setup but my car just launches in a straight line and just keeps pulling. Great mod don't be a baby turn up the music or stomp on the gas and you will not hear the LCA - Sour point by far which is sad because it's a beautiful peace is the 4 inch The Axle Exchange Driveshafts - Custom Seamless DOM Steel and 6061T6 Aluminum USA Made. KYB, Exedy, Centric Parts, Maval, Spicer, Daiken, Valeo, LuK, Neapco drive shaft with 1350 series.

Beautiful piece well built but this IS the culprit to my vibration problem hands down! My car is not lowered, pinion angle checked/tweaked several times, car ran on the hoist with rear tires lifted up, tires balanced 3 times, diff opened up twice to make sure gears were installed correctly and after the gear change is when the vibration was very noticeable at 65MPH. The issue is "the 4" shaft with the center mounted slip yolk are more likely to vibrate in a certain load range than the 3.5" shafts with a front mount yoke. There is something in the front of this drive shaft that is creating this vibration issue.

Does this vibrations always happen at the same speed regardless of RPM?

Mine always vibrated at 30mph no matter what rpm or which gear I had it in. Then I changed to 4.10s and now it vibrates at like 25mph. Dealer said they couldn't find anything, but I'm going to take it to Sutton Ford and see what they can find. Also seens to be a bit more noticable when hot. I'm thinking driveshaft.

Does this vibrations always happen at the same speed regardless of RPM?

Mine always vibrated at 30mph no matter what rpm or which gear I had it in. Then I changed to 4.10s and now it vibrates at like 25mph. Dealer said they couldn't find anything, but I'm going to take it to Sutton Ford and see what they can find. Also seens to be a bit more noticable when hot. I'm thinking driveshaft.

Good luck with it, it can be annoying as hell.

Same MPH this vibration happens and funny thing is you can pedal it say by 5MPH lower and it starts to decrease and it's way worse if you try to drive through it say 80MPH.

Take the driveshaft to a different shop that builds shafts for cars and trucks and has the proper equipment. I had a shaft done once that vibrated, the shop that built it said it was right on. I took it to a place that builds shafts for trucks and he rebalanced mine, said it was way off. After that the car ran real smooth at any speed. If the shaft is off, send the bill to Axle Exchange. Not saying anything bad about them, but it is possible the guy that built yours got distracted and it's off.

Take the driveshaft to a different shop that builds shafts for cars and trucks and has the proper equipment. I had a shaft done once that vibrated, the shop that built it said it was right on. I took it to a place that builds shafts for trucks and he rebalanced mine, said it was way off. After that the car ran real smooth at any speed. If the shaft is off, send the bill to Axle Exchange. Not saying anything bad about them, but it is possible the guy that built yours got distracted and it's off.

The Ford dealership took it off and had it sent to the driveline shop to check the balancing it was perfect. I also forgot to mention it was rotated 90 and 180 to check the phase with no change and that was done multiple times also. It has something to do with the front yoke.

Usually they balance the shaft with the yoke, but there's a possibility the inside dimensions could be off a slight bit which would make it ride differently in the tranny. Did anybody take a dial indicator on the shaft just after the front yoke while it was mounted to the tranny and see what the runout is when installed? That's one of the first things I check, some guys use a piece of chalk held against the spinning shaft, but the dial indicator is more accurate. Turn the shaft slowly without touching it. Put the tranny in neutral and rotate the tire so as to turn the shaft slowly. Also, move the shaft up and down and side to side to check both the joints and the play in the rear bushing of the tranny. You checked the angle of the pinion to make sure it matches the angle of the tranny in a vertical plane, did you check the alignment in a horizontal direction? Not usually off, but it would be a shame to assume it's correct and find out the rear is slightly angled or the tranny is angled because of a miss-stamped mount. Rare but possible. I'd be checking the runout and play of the front while installed.

You were typing while I was also. Do you have a picture of this installed in the car so we can get a better idea of what may be going on?

Usually they balance the shaft with the yoke, but there's a possibility the inside dimensions could be off a slight bit which would make it ride differently in the tranny. Did anybody take a dial indicator on the shaft just after the front yoke while it was mounted to the tranny and see what the runout is when installed? That's one of the first things I check, some guys use a piece of chalk held against the spinning shaft, but the dial indicator is more accurate. Turn the shaft slowly without touching it. Put the tranny in neutral and rotate the tire so as to turn the shaft slowly. Also, move the shaft up and down and side to side to check both the joints and the play in the rear bushing of the tranny. You checked the angle of the pinion to make sure it matches the angle of the tranny in a vertical plane, did you check the alignment in a horizontal direction? Not usually off, but it would be a shame to assume it's correct and find out the rear is slightly angled or the tranny is angled because of a miss-stamped mount. Rare but possible. I'd be checking the runout and play of the front while installed.

You were typing while I was also. Do you have a picture of this installed in the car so we can get a better idea of what may be going on?

Yes a few people also checked what you mentioned it was also mentioned it probably was something with the dimensions on the inside because spinning by the tire up at the front was .005 all the way through from front, middle and rear. I will try and take a picture tomorrow and post it.

Does this vibrations always happen at the same speed regardless of RPM?

Mine always vibrated at 30mph no matter what rpm or which gear I had it in. Then I changed to 4.10s and now it vibrates at like 25mph. Dealer said they couldn't find anything, but I'm going to take it to Sutton Ford and see what they can find. Also seens to be a bit more noticable when hot. I'm thinking driveshaft.

Good luck with it, it can be annoying as hell.

You driveshaft will spin faster when you change to lower gears. Each shaft has a natural resonance where it will vibrate, but from what I have read it is somewhere in the 4k rpm range up. My aluminum shaft cured all vibrations up to about 90mph with 3:31s and has a very small vibration up to about 120 or so. Above that I am scared enough not to notice a small vibration. The two piece from ford is junk and I cant believe they are still using it, especially on cars like the Boss. GA

I had the same problem. Didn't notice the vibration until about 55 and up. Faster I went, the worse it got. In throttle not bad, let off throttle and horrible. My shaft is 3.5" aluminum built by local driveshaft guy but he did not balance it due to the weird trans flange. Trutrac, 4.10, 03 cobra pinion flange, stock height, all rod ends on UCA & LCA's, neg 1.5 pinion angle. My car was at Bridge Racing last week for battery relocation and I asked him to pull the shaft and have it balanced while he had the car. The driveshaft shop he used said it was "clocked wrong", meaning the splined part of the slip joint needed to be pulled out, lined up correctly and slid back together. After they did this and balanced it it is vibration free in or out of the throttle all the way to 130 so far. Hope this helps.

The driveshaft will turn a certain rate dependent on speed of the car. If you're going 20 mph and shift to a different gear and hold 20 mph, the driveshaft will not change speed. The engine will speed up if you downshift but the driveshaft will spin at the same speed.

This assumes you aren't driving a newer Corvette which has the driveshaft before the tranny.

The drive shaft will turn a certain rate dependent on speed of the car. If you're going 20 mph and shift to a different gear and hold 20 mph, the drive shaft will not change speed. The engine will speed up if you downshift but the drive shaft will spin at the same speed.

This assumes you aren't driving a newer Corvette which has the drive shaft before the tyranny.